I learned CFD recently and I have a question about Fluent. I'm creating a User Define Function that will add a source momentum to the Navier-Stokes equations. The source momentum consist of a set of force vectors (Fx,Fy).

Does the forces in fluent are node centered or cell centered ? And what about the units for the force (N, N/m, N/m^2 or N/m^3 ?)